Fungal feeding preferences and molecular gut content analysis of two abundant oribatid mite species (Acari: Oribatida) under the canopy of Prosopis laevigata (Fabaceae) in a semi-arid land.

Prosopis laevigata (mesquite; Fabaceae) forms fertility islands in soils of semi-arid lands where microbial diversity concentrates in response to the accumulation of resources in the soil beneath individual plants, promoting organic matter decomposition and nutrient cycling. This phenomenon provides suitable conditions for the proliferation of key edaphic elements such as fungi and mites. Mite-fungal interactions are central for our understanding of nutrient cycling processes in resource-limited arid food webs; yet, no information is available about fertility islands in semi-arid lands. Thus, we aimed to determine in vitro fungal-based feeding preferences and molecular gut content of the oribatid mite species Zygoribatula cf. floridana and Scheloribates cf. laevigatus, which are abundant under the canopy of P. laevigata in an intertropical semi-arid zone in Central Mexico. Our results on the gut content analysis of these oribatid species resulted in the ITS-based identification of the following fungi: Aspergillus homomorphus, Beauveria bassiana, Filobasidium sp., Mortierella sp., Roussoella sp., Saccharomyces cerevisiae, Sclerotiniaceae sp. and Triparticalcar sp. Furthermore, under laboratory conditions both oribatid mite species exhibited feeding preferences on melanized fungi, such as Cladosporium spp., whereas A. homomorphus and Fusarium penzigi were avoided. Our findings indicated that the analyzed oribatid mite species have similar feeding preferences for melanized fungi, which might suggest resource partitioning and a degree of preference, explaining the coexistence of both oribatid species.

Traveler Mites: Population Genetic Structure of the Wing Mites Periglischrus paracaligus (Acari: Mesostigmata: Spinturnicidae).

Wing mites of the genus Periglischrus are ectoparasites exclusively associated with phyllostomid bats. These mites show high host specificity and have been studied to understand the evolutionary history of their bat hosts mainly by using a morphological variation. Through a phylogeographic approach, we analyzed the genetic diversity and population genetic structure of the ectoparasite Periglischrus paracaligus Herrin and Tipton which parasitizes Leptonycteris yerbabuenae Martínez and Villa (lesser long-nosed bat) in Mexico. By the implementation of a multilocus approach, we found that P. paracaligus populations were diverse for haplotype diversity, and had values ranging from 0.5 to 1. No genetic structuring in the P. paracaligus parasites was observed along with the distribution of the host, L. yerbabuenae, in Mexico, nor when populations or regions were compared, but our results revealed a process of historical demographic expansion in all the analyzed markers. We discuss possible scenarios that could explain the lack of population structure in the light of the data analyzed for the parasites and the biology of L. yerbabuenae, such as the interplay between parasite and host traits being responsible for the genetic make-up of parasite populations. We also inferred its phylogenetic position among wing mites parasitizing the two other species of Leptonycteris bats. Long-nosed bats' monophyly helps to explain the observed presence of distinctive clades in the wing mite's phylogeny in specific association with each long-nosed bat host species.

Morphological Variation in the Wing Mite Periglischrus paracaligus (Acari: Spinturnicidae) Associated With Different Moving Strategies of the Host Leptonycteris yerbabuenae (Chiroptera: Phyllostomidae).

We evaluated the morphometric variation of wing mite Periglischrus paracaligus Herrin and Tipton, along with the distribution of their host Leptonycteris yerbabuenae Martinez and Villa, in Mexico. A total of 115 female and 96 male specimens of P. paracaligus were used to conduct linear and geometric morphometric analyses. We assessed the influence of the geographic distribution of the migratory and nonmigratory populations of its bat host species on changes in size and shape on these parasites. Both analyses revealed high intraspecific variation in P. paracaligus, but subtle geographic differentiation. None of the approaches used identified a consistent pattern that separates unambiguously migratory from nonmigratory populations. Females presented more phenotypic variation than males and UPGMA analyses showed southern and northern colonies grouped in two distinct clades. Males on the other hand showed randomly grouped colonies with no geographic concordance. Interestingly, the most differentiated colony was the north Pacific colony of Jalisco. For both, males and females, isolation by distance (IBD) was not observed. We discuss these results as a possible scenario of contact between migratory populations located in northern Mexico with nonmigratory populations in other localities in central and southern Mexico conforming to a panmictic population along with their distribution range.

Ornithodoros dyeri (Parasitiformes: Ixodida: Argasidae) parasitizing Leptonycteris yerbabuenae (Chiroptera: Phyllostomidae) in Mexico.

Parasites are a selective force that shape communities and ecosystems. Hosts represent a food source, habitat, and a way to disperse. In recent years, investigations dealing with bats and their role as hosts to numerous parasitic organisms, including metazoan ectoparasites and endoparasites have increased, and soft ticks (Parasitiformes: Ixodida: Argasidae) are among the best known. In Mexico, 16 species of soft ticks associated with bats have been reported up to now, but there are no specific records of soft ticks parasitizing Leptonycteris yerbabuenae in the country. Herein, we record for the first time the presence of Ornithodoros dyeri parasitizing L. yerbabuenae and report an extension of its geographic distribution. The same tick species was also recorded from the California leaf-nosed bat (Macrotus californicus). Data on prevalence, mean intensity, mean abundance, tick identification, and possible scenarios of life cycle associations for O. dyeri and one of its hosts, L. yerbabuenae, are discussed.

Kir7.1 inwardly rectifying K+ channel is expressed in ciliary body non pigment epithelial cells and might contribute to intraocular pressure regulation.

Inwardly rectifying K+ channel Kir7.1 is expressed in epithelia where it shares membrane localisation with the Na+/K+-pump. The ciliary body epithelium (CBE) of the eye is a determinant of intraocular pressure (IOP) through NaCl-driven fluid secretion of aqueous humour. In the present study we explored the presence Kir7.1 in this epithelium in the mouse and its possible functional role in the generation of IOP. Use heterozygous animals for total Kir7.1 knockout expressing ß-galactosidase under the control of Kir7.1 promoter, identified the expression of Kir7.1 in non-pigmented epithelial cells of CBE. Using conditional, floxed knockout Kir7.1 mice as negative controls, we found Kir7.1 at the basolateral membrane of the same CBE cell layer. This was confirmed using a knockin mouse expressing the Kir7.1 protein tagged with a haemagglutinin epitope. Measurements using the conditional knockout mouse show only a minor effect of Kir7.1 inactivation on steady-state IOP. Transient increases in IOP in response to general anaesthetics, or to water injection, are absent or markedly curtailed in Kir7.1-deficient mice. These results suggest a role for Kir7.1 in IOP regulation through a possible modulation of aqueous humour production by the CBE non-pigmented epithelial cells. The location of Kir7.1 in the CBE, together with the effect of its removal on dynamic changes in IOP, point to a possible role of the channel as a leak pathway preventing cellular overload of K+ during the secretion process. Kir7.1 could be used as a potential therapeutic target in pathological conditions leading to elevated intraocular pressure.

Experimental and molecular approximation to microbial niche: trophic interactions between oribatid mites and microfungi in an oligotrophic freshwater system.

Mite-fungal interactions play a key role in structuring core ecosystem processes such as nutrient dynamics. Despite their ecological relevance, these cross-kingdom interactions remain poorly understood particularly in extreme environments. Herein, we investigated feeding preferences of a novel genetic lineage of aquatic oribatids obtained from an oligotrophic freshwater system in the Cuatro Ciénegas Basin (CCB) within the Chihuahuan Desert, Mexico. During in vitro diet preference bioassays, transient aquatic microfungi (Aspergillus niger, Talaromyces sp., and Pleosporales sp.) recovered from the same mesocosm samples were offered individually and simultaneously to mites. Gut content was analyzed using classic plating and culture-independent direct PCR (focusing on the fungal barcoding region) methods. Our results indicated that oribatids fed on all tested fungal isolates, yet the profusely developing A. niger was preferentially consumed with all fungal components being digested. This feeding habit is particularly interesting since A. niger has been reported as an unsuitable dietary element for population growth, being consistently avoided by mites in previous laboratory experiments. It is possible that our mites from the CCB have adapted to exploit available resources within this oligotrophic site. This work confirms the trophic relationship between microfungi and mites, two rarely investigated major components of the microbial community, shedding light on the niche dynamics under low-nutrient conditions.

K2P TASK-2 and KCNQ1-KCNE3 K+ channels are major players contributing to intestinal anion and fluid secretion.

KEY POINTS: K+ channels are important in intestinal epithelium as they ensure the ionic homeostasis and electrical potential of epithelial cells during anion and fluid secretion. Intestinal epithelium cAMP-activated anion secretion depends on the activity of the (also cAMP dependent) KCNQ1-KCNE3 K+ channel, but the secretory process survives after genetic inactivation of the K+ channel in the mouse. Here we use double mutant mice to investigate which alternative K+ channels come into action to compensate for the absence of KCNQ1-KCNE3 K+ channels. Our data establish that whilst Ca2+ -activated KCa 3.1 channels are not involved, K2P two-pore domain TASK-2 K+ channels are major players providing an alternative conductance to sustain the intestinal secretory process. Work with double mutant mice lacking both TASK-2 and KCNQ1-KCNE3 channels nevertheless points to yet-unidentified K+ channels that contribute to the robustness of the cAMP-activated anion secretion process. ABSTRACT: Anion and fluid secretion across the intestinal epithelium, a process altered in cystic fibrosis and secretory diarrhoea, is mediated by cAMP-activated CFTR Cl- channels and requires the simultaneous activity of basolateral K+ channels to maintain cellular ionic homeostasis and membrane potential. This function is fulfilled by the cAMP-activated K+ channel formed by the association of pore-forming KCNQ1 with its obligatory KCNE3 ß-subunit. Studies using mice show sizeable cAMP-activated intestinal anion secretion in the absence of either KCNQ1 or KCNE3 suggesting that an alternative K+ conductance must compensate for the loss of KCNQ1-KCNE3 activity. We used double mutant mouse and pharmacological approaches to identify such a conductance. Ca2+ -dependent anion secretion can also be supported by Ca2+ -dependent KCa 3.1 channels after independent CFTR activation, but cAMP-dependent anion secretion is not further decreased in the combined absence of KCa 3.1 and KCNQ1-KCNE3 K+ channel activity. We show that the K2P K+ channel TASK-2 is expressed in the epithelium of the small and large intestine. Tetrapentylammonium, a TASK-2 inhibitor, abolishes anion secretory current remaining in the absence of KCNQ1-KCNE3 activity. A double mutant mouse lacking both KCNQ1-KCNE3 and TASK-2 showed a much reduced cAMP-mediated anion secretion compared to that observed in the single KCNQ1-KCNE3 deficient mouse. We conclude that KCNQ1-KCNE3 and TASK-2 play major roles in the intestinal anion and fluid secretory phenotype. The persistence of an, admittedly reduced, secretory activity in the absence of these two conductances suggests that further additional K+ channel(s) as yet unidentified contribute to the robustness of the intestinal anion secretory process.

Redescription of Periglischrus herrerai (Acari: Spinturnicidae) Associated to Desmodus rotundus (Chiroptera: Phyllostomidae: Desmodontinae), With a Description of Adult Female Heteromorphism and an Analysis of its Variability Throughout the Neotropics.

A redescription, with a discussion of new features and illustrations, for all life stages is presented for the parasitic mite Periglischrus herrerai Machado-Allison associated with the common vampire bat Desmodus rotundus (Geoffoy), including a description of the heteromorphic female and the first description of its female deutonymph. In addition, the morphological variation of P. herrerai is evaluated by morphometric analysis of the adults, concluding that there is an evident geographic variation throughout the neotropics. This study was possible by using type material of P. herrerai from the Machado-Allison collection, and voucher specimens from other collections, and specimens from an extensive surveying of hematophagous bats in some localities of the Pacific and Atlantic versants, and central Mexico.

Isolation and multilineage differentiation of bone marrow mesenchymal stem cells from abattoir-derived bovine fetuses.

BACKGROUND: Mesenchymal stem cells (MSC) are multipotent progenitor cells localized in the stromal compartment of the bone marrow (BM). The potential of MSC for mesenchymal differentiation has been well documented in different animal models predominantly on rodents. However, information regarding bovine MSC (bMSC) is limited, and the differentiation potential of bMSC derived from fetal BM remains unknown. In the present study we sought to isolate bMSC from abattoir-derived fetal BM and to characterize the multipotent and differentiation potential under osteogenic, chondrogenic and adipogenic conditions by quantitative and qualitative analyses. RESULTS: Plastic-adherent bMSC isolated from fetal BM maintained a fibroblast-like morphology under monolayer culture conditions. These cells expressed high levels of MSC surface markers (CD73, CD90, and CD105) and low levels of hematopoietic surface markers (CD34 and CD45). Culture of bMSC under osteogenic conditions during a 27-day period induced up-regulation of the osteocalcin (OC) gene expression and alkaline phosphatase (ALPL) activity, and promoted mineralization of the matrix. Increasing supplementation levels of ascorbic acid to culture media enhanced osteogenic differentiation of bMSC; whereas, reduction of FBS supplementation compromised osteogenesis. bMSC increased expression of cartilage-specific genes aggrecan (ACAN), collagen 2A1 (COL2A1) and SRY (sex-determining region Y) box 9 (SOX9) at Day 21 of chondrogenic differentiation. Treatment of bMSC with adipogenic factors increased levels of fatty acid-binding protein 2 (AP2) mRNA and accumulation of lipid vacuoles after 18 days of culture. NANOG mRNA levels in differentiating bMSC were not affected during adipogenic culture; however, osteogenic and chondrogenic conditions induced higher and lower levels, respectively. CONCLUSIONS: Our analyses revealed the potential multilineage differentiation of bMSC isolated from abattoir-derived fetal BM. NANOG mRNA pattern in differentiating bMSC varied according to differentiation culture conditions. The osteogenic differentiation of bMSC was affected by ascorbic acid and FBS concentrations in culture media. The simplicity of isolation and the differentiation potential suggest that bMSC from abattoir-derived fetal BM are appropriate candidate for investigating MSC biology and for eventual applications for regenerative therapy.

Radiologic morphology of the calcaneus: a study of radiologic angles in a pediatric population.

BACKGROUND: The Fowler-Philip, calcaneal pitch, and total calcaneal angles define the radiologic morphology of the rearfoot. We studied these angles in healthy adolescents. METHODS: We studied 141 feet. Patients with inflammatory or traumatic injuries were excluded. The mean participant age was 11.5 years. The Fowler-Philip, calcaneal pitch, and total calcaneal angles were measured on lateral weightbearing radiographs. The statistics included descriptive, sample size (α=0.05 and ß=0.20), the Student t test, and analysis of variance; P < .05 was considered significant. RESULTS: The samples were 141 and 35 radiographs for the Fowler-Philip and calcaneal pitch angles, respectively. Ninety percent, 25.1%, and 97.4% of the adolescents had normal Fowler-Philip, calcaneal pitch, and total calcaneal angles, respectively. In addition, 9.9%, 74.9%, and 2.6% of the values were outside the reference ranges, respectively. The Fowler-Philip angle decreased and the calcaneal pitch angle increased significantly with age (P = .0005). The total calcaneal angle did not change with age (P = .65). CONCLUSIONS: The mean angle values in a pediatric population did not differ from those in adults. We found a high percentage of calcaneal pitch angles outside the reference range. Age influenced the Fowler-Philip and calcaneal pitch angles but not the total calcaneal angle.

Aneurismas múltiples en la arteria pulmonar / Multiple aneurysms in the pulmonary arteries

La presencia de aneurismas en las arterias pulmonares son hallazgos poco frecuentes. Gran parte de estos aneurismas necesitan ser confirmados por angiografía pulmonar. Existe una alta asociación con malformaciones arterio venosas, pero en el presente caso no fueron demostradas por ecocontraste ni por angiografía pulmonar. Un dato relevante para el diagnóstico del presente caso fue el compromiso arterial sistémico. Las diferentes causas que pueden generar aneurismas pulmonares no son siempre fáciles de identificar y las dificultades para establecer una estrategia diagnóstica y terapéutica adecuada en estos pacientes motivaron el reporte del presente caso